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Title: Turbulent Magnetic Relaxation in Pulsar Wind Nebulae

Abstract

We present a model for magnetic energy dissipation in a pulsar wind nebula. A better understanding of this process is required to assess the likelihood that certain astrophysical transients may be powered by the spin-down of a “millisecond magnetar.” Examples include superluminous supernovae, gamma-ray bursts, and anticipated electromagnetic counterparts to gravitational wave detections of binary neutron star coalescence. Our model leverages recent progress in the theory of turbulent magnetic relaxation to specify a dissipative closure of the stationary magnetohydrodynamic (MHD) wind equations, yielding predictions of the magnetic energy dissipation rate throughout the nebula. Synchrotron losses are self-consistently treated. To demonstrate the model’s efficacy, we show that it can reproduce many features of the Crab Nebula, including its expansion speed, radiative efficiency, peak photon energy, and mean magnetic field strength. Unlike ideal MHD models of the Crab (which lead to the so-called σ -problem), our model accounts for the transition from ultra to weakly magnetized plasma flow and for the associated heating of relativistic electrons. We discuss how the predicted heating rates may be utilized to improve upon models of particle transport and acceleration in pulsar wind nebulae. We also discuss implications for the Crab Nebula’s γ -ray flares, and pointmore » out potential modifications to models of astrophysical transients invoking the spin-down of a millisecond magnetar.« less

Authors:
 [1];  [2]
  1. Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States)
  2. Astronomy Department and Theoretical Astrophysics Center, University of California, Berkeley, 601 Campbell Hall, Berkeley, CA 94720 (United States)
Publication Date:
OSTI Identifier:
22679832
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 847; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; COSMIC GAMMA BURSTS; CRAB NEBULA; ENERGY LOSSES; GRAVITATIONAL WAVES; MAGNETIC FIELDS; MAGNETIC RECONNECTION; MAGNETOHYDRODYNAMICS; NEUTRON STARS; NEUTRONS; PLASMA; PULSARS; RELATIVISTIC RANGE; RELAXATION; STELLAR WINDS; SUPERNOVAE; SYNCHROTRON RADIATION; TURBULENCE; VELOCITY

Citation Formats

Zrake, Jonathan, and Arons, Jonathan. Turbulent Magnetic Relaxation in Pulsar Wind Nebulae. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA826D.
Zrake, Jonathan, & Arons, Jonathan. Turbulent Magnetic Relaxation in Pulsar Wind Nebulae. United States. doi:10.3847/1538-4357/AA826D.
Zrake, Jonathan, and Arons, Jonathan. Wed . "Turbulent Magnetic Relaxation in Pulsar Wind Nebulae". United States. doi:10.3847/1538-4357/AA826D.
@article{osti_22679832,
title = {Turbulent Magnetic Relaxation in Pulsar Wind Nebulae},
author = {Zrake, Jonathan and Arons, Jonathan},
abstractNote = {We present a model for magnetic energy dissipation in a pulsar wind nebula. A better understanding of this process is required to assess the likelihood that certain astrophysical transients may be powered by the spin-down of a “millisecond magnetar.” Examples include superluminous supernovae, gamma-ray bursts, and anticipated electromagnetic counterparts to gravitational wave detections of binary neutron star coalescence. Our model leverages recent progress in the theory of turbulent magnetic relaxation to specify a dissipative closure of the stationary magnetohydrodynamic (MHD) wind equations, yielding predictions of the magnetic energy dissipation rate throughout the nebula. Synchrotron losses are self-consistently treated. To demonstrate the model’s efficacy, we show that it can reproduce many features of the Crab Nebula, including its expansion speed, radiative efficiency, peak photon energy, and mean magnetic field strength. Unlike ideal MHD models of the Crab (which lead to the so-called σ -problem), our model accounts for the transition from ultra to weakly magnetized plasma flow and for the associated heating of relativistic electrons. We discuss how the predicted heating rates may be utilized to improve upon models of particle transport and acceleration in pulsar wind nebulae. We also discuss implications for the Crab Nebula’s γ -ray flares, and point out potential modifications to models of astrophysical transients invoking the spin-down of a millisecond magnetar.},
doi = {10.3847/1538-4357/AA826D},
journal = {Astrophysical Journal},
number = 1,
volume = 847,
place = {United States},
year = {Wed Sep 20 00:00:00 EDT 2017},
month = {Wed Sep 20 00:00:00 EDT 2017}
}